Self-cleaning pressure filter systems are known.
In systems of this kind available from the assignee of this invention, liquid to be filtered enters the interior of a circular cross section, cylindrical filter element, is filtered by passing radially outward through the perforate wall of the filter element and exits as a filtered liquid from the housing containing the filter element. A rotary cleaning unit orbits a longitudinally extending doctor and wiper circumferentially along the inner face of the filter element for the purpose of reducing the build-up of filtered-out solids on the inner face of the filter element. The purpose is to reduce the amount of backwashing required to maintain filtering efficiency, and thereby to reduce the percentage of down time of the filter system.
Although this prior system works well, the present Applicant has found that continuous cleaning can be achieved without need for cleaning elements extending axially the length of the filter element.
Accordingly, the objects and purposes of the present invention include provision of a self-cleaning filter system in which a cleaning element axially reciprocable along the unfiltered liquid side of the filter element cleans filtered-out solids therefrom, in which the same size axially reciprocable cleaning element can be used in filter elements of any length, in which several cleaning elements may be located to simultaneously clean the filter element, in which the build-up of filtered-out solids is minimized on the entire circumference of the filter element, in which the filter element may be cleaned by doctoring and/or wiping actions, in which the filter element and cleaning element are readily removed from the filter housing for repair or replacement, and in which the cleaning apparatus can be constructed at relatively low cost from commonly available materials without special tools.
Further objects and purposes of the invention will be apparent to persons acquainted with apparatus of this general type upon reading the following description and inspecting the accompanying drawings.